Dr. Horrible's Sing-Along Blog: When his freeze ray powers down, Dr. Horrible has just enough time to note "That's not a good sound..." before his face gets introduced to the now-free Captain Hammer's fist. Again.

Survival of the Fittest has Cody Jenson do this at the end of V1. He finishes off Sidney Crosby, who attacked him to save Adam Dodd, and then turns around just in time to see a very angry Adam Dodd attacking him with a katana. A quick 'Oh crap!' moment, considering that he gets stabbed and impaled almost immediately.

Also happens to Harry Tsai in V3, when he sees Andrea Vanlandingham's detached collar, whom he killed earlier in the game, moments before Denise Dupuis wreaks her vengeance upon him.

In his Top 11 F* ck Ups special, The Nostalgia Critic decides to hunt down Douchy McNitpick. Douchy is confident that there's no way the NC will find him, until he hears a window in his house breaking.

During the RP of The Marios, this is the trio's general reaction when the creator of the bad LP in question, LuwiigiMaster, disses Retsupurae during his LP. Diabetus later comments that he should pre-screen LPs before bringing the gang over to riff them. If one reads the comments, the guy apparently was trying to purposely make a So Bad It's Good video just to get RPed.

Luigi, upon realizing that Mecha Sonic is about to Spirit BombDeath Ball the fucking hell out of their island Frieza-style, releases a single, utterly hilarious scream of sheer terror. It is FANTASTIC.